1 / 12

HP Optical Media Advance System (OMAS)

HP Optical Media Advance System (OMAS). Media Advance motion encoding (1). Most large format printers measure motion of the media indirectly by encoding an element in the drive system motor shaft (least accurate) final drive roller (most accurate)

kawena
Download Presentation

HP Optical Media Advance System (OMAS)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. HP Optical Media Advance System (OMAS)

  2. Media Advancemotion encoding (1) • Most large format printers measure motion of the media indirectly by encoding an element in the drive system • motor shaft (least accurate) • final drive roller (most accurate) • The drive system can be calibratedby comparing input (motor) and output (media) motions to minimize systematic errors from... • media physical properties • media slippage • Indirect measurements are... • adequate for moves less than ~1 inch • subject to errors from • media slippage • temperature and humidity changes • mechanical tolerances and wear encoder mediadrive motor final drive roller final drive roller encoder print zone

  3. Media Advancesteady advances in accuracy • Since 1990, HP has achieved a 20X improvement in the accuracy of encoder-based media advance systems in HP Designjet printers • Improvements are driven by • larger print swaths, longer moves • need for higher image qualityat higher throughput • Encoder-based systems are reaching practical limits at ~1um/mm (0.1%) • requires high mechanical precision • increases manufacturing cost • Wider printheads and HP Double Swath Technology need longer mediamoves to achieve potential speed • accuracies better than 0.5um/mm are needed for long moves (~2 inches) • a performance breakthrough is neededin media advance accuracy Media Advance Accuracy (um/mm) 100.0 10.0 DJ 4000 DJ 5500 1.0 target 0.1 1985 1990 1995 2000 2005 2010 HP Designjets by Year of Introduction

  4. better OMASeffective improvement in image quality • Results from comparative testing with and without OMAS • internal HP tests with a pool of image quality judges • controlled viewing environment • best sample rated “100” • images ranked in bands: “better”, “worse”, “acceptable” • CAD drawing, Normal Mode, HP Bond Paper mean value confidence band Banding(higher number = better) Line Smoothness(higher number = better) no OMAS30% RH 100 100 no OMAS30% RH 80 80 60 60 no OMAS70% RH Relative image quality OMAS30% RH OMAS70% RH no OMAS70% RH 40 40 OMAS30% RH OMAS70% RH 20 20 0 0 Samples printed with OMAS show less banding and better line smoothness. Consistent OMAS results for printing conditions between 30% and 70% RH.

  5. AB dX Image A dY OMAShow it works (1) media back side • OMAS takes images A and B in two “windows” • Separation distance AB (~3mm) is measured with high precision during OMAS manufacture • AB is stored in the OMAS EEPROM windowA • OMAS stores reference image A from window A • The media moves ~AB in the X-direction • window B now sees the same region of the media that was stored in reference image A X windowB • OMAS takes new images A’ and B’ • window A: image A’ (used for the next AB step) • window B: image B’ (used to match with image A) • image B’ is now correlated (matched) to image A • algorithms compute the offsets dX and dY between images A and B’ • OMAS reports the media has moved ΔX = AB + dX • dX and dY will be different on each AB step • dX and dY may be positive or negative Image B’

More Related